As silicon technologies have advanced, the bandwidth at which circuits utilizing those technologies can perform has also advanced. Packaging these circuits (e.g., those capable of bandwidths up to approximately 100 Giga-Hertz (GHz)) can be particularly challenging as silicon technologies have advanced. Some conventional approaches have involved using wafer level chip scale packaging (WLCSP) for some millimeter-wave circuit products. WLCSP involves mounting a chip directly on a printed circuit board (PCB), eliminating the need for a package carrier (employed in older approaches).
However, conventional WLCSP has shortcomings, including for example: a) standard conventional WLCSP uses relatively large ball diameters (approximately 250 micrometers (um) for 400 um pitch-minimum ball pitch on PCB for current cost effectiveness) and height (approximately 200 um for 250 um ball diameter). This conventional WLCSP has been shown to incur a −10 dB return loss bandwidth of approximately 70 GHz; and b) specialized conventional WLCSP designs use relatively small ball diameters, e.g., approximately 30 um to approximately 100 um, which may extend the bandwidth of the packaging to approximately 100 GHz. However, the specialized designs have higher manufacturing costs (relative to the standard designs), can cause wafer test issues due to the small ball size, and can also have performance inconsistency between designs utilizing and not utilizing PCB pads, which may result in wafer test yield issues.